$OpenBSD: patch-lib_sockopt_h,v 1.1 2013/01/04 00:24:10 sthen Exp $

Revert 69bf3a39; does not work on at least (Open/Net)BSD.
This can be put back if we get RFC3678 support.

--- lib/sockopt.h.orig	Tue Apr 17 14:56:26 2012
+++ lib/sockopt.h	Thu Jan  3 00:24:26 2013
@@ -83,11 +83,13 @@ extern int setsockopt_ipv6_tclass (int, int);
   (((af) == AF_INET) : SOPT_SIZE_CMSG_IFINDEX_IPV4() \
                     ? SOPT_SIZE_CMSG_PKTINFO_IPV6())
 
-extern int setsockopt_ipv4_multicast_if(int sock,
-			             unsigned int ifindex);
-extern int setsockopt_ipv4_multicast(int sock, int optname,
+extern int setsockopt_multicast_ipv4(int sock, int optname, 
+			             struct in_addr if_addr
+					 /* required: interface to join on */,
                                      unsigned int mcast_addr,
-			             unsigned int ifindex);
+			             unsigned int ifindex
+					 /* optional: if non-zero, may be used
+					 	instead of if_addr */);
 extern int setsockopt_ipv4_tos(int sock, int tos);
 
 /* Ask for, and get, ifindex, by whatever method is supported. */
